Accurate analysis of the components of body composition can lay the ground work for the comprehension and prevention of various disease processes; however, such data are lacking for children, especially by the more accurate 4-component model We will specifically address the role of gonadal steroid hormones by comparing groups with deficiencies of these hormones (e.g., Turner syndrome, C DGA) or previous excessive levels (precocious puberty) to normally growing children, also taking into consideration nutrition and changes in GH and the adrenal steroids. We continue to enroll subjects.